John S. Wood

Synthesis, spectroscopy and X-ray structure of hexakis(μ-3-methyl-4-ethyl-1,2,4-triazolo-N1,N2)tetraaquatricopper(II) hexakis(trifluoromethylsulfonate)

The synthesis, characterization and X-ray structure determination of [Cu 3 (metz) 6 (H 2 O) 4 ] (CF 3 SO 3 ) 6 (H 2 O) 4 is described. The compound crystallizes in the space group R , with a = b = 14.075(3) and c = 34.655(8) A. The complex cation consists of linear trinuclear clusters positioned on the crystallographic three-fold axis, and in which the Cu atoms are bridged by triple N 1 ,N 2 -coordinating triazole ligands. The terminal copper atoms are in addition coordinated by two water molecules, and thus have a distorted tetragonal pyramidal geometry. The central copper ion is located at a three-fold inversion center and thus should exhibit dynamic Jahn-Teller behaviour. In the crystal one observes the average of three such trimers related by the three-fold axis, and due to this disorder and also to that in the triflate anions, the structure could be refined only to R = 0.17 ( R w = 0.20). The infrared and ligand-field spectroscopic data and magnetic susceptibility are in agreement with the observed structure.

Transition metal complexes of two related pyrazole containing ligands:3,6-dimethyl-1,8-(3,5-dimethyl-1-pyrazolyl)-3,6-diazaoctane (ddad) and 1,4-bis(2-ethyl-(3,5-dimethyl-1-pyrazolyl))-piperazine (bedp). Synthesis, spectroscopy and X-ray structures

Abstract Several coordination compounds with the ligand 3,6-dimethyl-1,8-(3,5-dimethyl-1-pyrazolyl)-3,6-diaza- octane (ddad) were obtained: (Cu, Ni)(ddad)(BF 4 ) 2 , Co(ddad)(H 2 O)(BF 4 ) 2 , (Co, Ni, Cu, Zn) 2 (ddad)Cl 4 , Co 3 (ddad) 2 (NCS) 6 and Cu 2 (ddad)(NCS) 3 . Five X-ray structures were obtained, viz. of [Cu(ddad)](BF 4 ) 2 , [Ni(ddad)](BF 4 ) 2 , Ni(ddad)(NCS) 2 , [Ni(bedp)](H 2 O)(BF 4 ) 2 and [Cu(bedp)](H 2 O)(BF 4 ) 2 , but the data did not allow the calculation of very accurate bond lengths. However, the basic coordination geometries were obtained in all cases. The coordination by the ligands is square planar, while Ni(ddad)(NCS) 2 contains additional trans coordinating thiocyanate anions. The asymmetric unit of [Cu(ddad)](BF 4 ) 2 contains two almost identical [Cu(ddad)] 2+ species. The coordination of the copper atoms in both molecules is intermediate between tetrahedral and square planar. One molecule [Cu(ddad)] 2+ is the (R,R) diastereoisomer of the ligand and the other is the (S,S) diastereoisomer. The chloride compounds are, except for Ni(II), all dinuclear with MN 2 Cl 2 chromophores. The nickel(II) compound contains square planar Ni(ddad) 2+ cations and tetrahedral NiCl 4 2- anions. The thiocyanate compound of Ni(II), which is isomorphous with the corresponding Zn(II) compound, has octahedral MN 2 N 2 ′N 2 ″ chromophores. The cobalt compound crystallizes as [Co(ddad)(NCS)] 2 Co(NCS) 4 with five coordinate cobalt in the cation. With copper thiocyanate ddad forms the mixed-valence compound Cu 2 (ddad)(NCS) 3 , with [Cu(ddad)] 2+ and [Cu(NCS) 3 ] 2- . With the ligand, 1,4-bis(2-ethyl-(3,5-dimethyl-l-pyrazolyl))-piperazine (bedp) the compounds [(Ni, Cu)Coedp)](H 2 O)(BF 4 ) 2 , (Ni, CO)Coedp)(NCS) 2 , Zn 2 (bedp)(NCS) 4 , (Ni, Co, Cu, Zn) 2 (bedp)Cl 4 and Cu 2 (bedp)(NCS) 3 were obtained. The chloride compounds form dinuclear compounds (similar to ddad) with MN 2 Cl 2 chromophores. However, in addition to the green form of [Ni(bedp)][NiCl 4 ] a purple isomer Ni 2 (bedp)Cl 4 , with a tetrahedral NiN 2 Cl 2 chromophore, was obtained. The ligand field spectra of Ni(bedp)(NCS) 2 and the isomorphous cobalt compound show typical octahedral chromophores. With copper thiocyanate a mixed-valence compound was formed, with a structure likely to be similar to the corresponding ddad compound, viz. [Cu(II)(bedp)][Cu(I)(SCN) 3 ].

Synthesis of (phosphine)silver(I) trifluoromethanesulfonate complexes and the molecular structure of di-μ-trifluoromethylsulfonate-(tetrakis-triphenylphosphine)disilver(I)

Abstract Reactions of silver trifluoromethanesulfonate (triflate) and equimolar amounts of triphenylphosphine, 1,2-bis(diphenylphosphino)ethane, bis(diphenylphosphino)methane, or 1,1-bis(diphenylphosphino)ethane in either DME or CH 2 Cl 2 solution produced the corresponding 1:1 complexes [(L)Ag(I)(SO 3 CF 3 )] ( 2 – 5 ) in >80% yields. A related 2:1 complex [(Ph 3 P) 2 Ag(I)(SO 3 CF 3 )] ( 1 ) was also obtained using 2 equiv. of Ph 3 Ph. Both 31 P NMR variable temperature solution spectra as well as solid state spectra were recorded for the new complexes, and were generally helpful in structural assignments. An X-ray crystallographic study of 1 shows this to be a dimeric complex with bridging triflate ions; the silver atoms having distorted tetrahedral coordination.

Coordination behavior of the ligand 1,9-bis(3,5-dimethyl-1-pyrazolyl)-3,7-dithianonane (bddn) towards first-row transition metals. X-ray structure of [Cu(bddn)(H2O)](BF4)2

Abstract The synthesis and characterization of the ligand 1,9-bis(3,5-dimethyl-1-pyrazolyl)-3,7-dithianonane (bddn) and its coordination compounds, viz. [M(L)(X) 2 ] where M is Co 2+ , Zn 2+ ; X is Cl − , Br − , NCS − , and [Cu(L)(H 2 O)](BF 4 ) 2 are described. The X-ray structure of [Cu(bddn)(H 2 O)](BF 4 ) 2 has been determined. The compound crystallizes from ethanol in the monoclinic space group P 2 1 / c with unit-cell parameters a =18.508(5), b =9.253(3), c =15.743(5) A, β=107.91(3)°, V =2565.5 A 3 , D calc =1.57 g/cm 3 for Z =4. The structure was refined to R =0.099 and R w =0.116 for 1841 unique reflections with I >σ( I ). The copper(II) ion is coordinated by two pyrazole nitrogen donors, two thioether donors and a water molecule in a trigonal bipyramidal environment, with the two pyrazoles in an unusual cis position. The donor atoms at the axial positions area nitrogen and a sulfur, the equatorial plane donors are nitrogen, sulfur and the oxygen atom. From the ligand field spectra, the infrared patterns and the X-ray powder patterns it was concluded that the structures of the cobalt(II)- and zinc(II)-containing compounds are structurally similar to Zn(bddo)(NCS) 2 , a previously reported chain like structure with an MN 2 N′ 2 chromophore, in which the ligand S atoms do not bind to the metal ion.

Transition metal compounds of a chelating imidazole-thioether-amine ligand. Crystal and molecular structures of (4-(5-methyl-4-imidazolyl)-1-amino-3-thiabutane)di(chloro)copper(II), bis(4-(5-methyl-4-imidazolyl)-1-amino-3-thiabutane)copper(II) dichloride dihydrate, and bis(4-(5-methyl-4-imidazolyl)- 1-amino-3-thiabutane)cobalt (III) tris(tetrafluoroborate)

Abstract The synthesis and characterization of a series of monomeric transition metal coordination compounds with the ligand 4-(5-methyl-4-imidazolyl)-1-amino-3-thiabutane (abbreviated memia) are described, viz. [M(memia)Cl 2 ](H 2 O) n , with MCo, Ni, Cu; [M(memia) 2 ]X 2 (H 2 O) n , with MNi, Cu and XCl, NO 3 , BF 4 ; and [Co(memia) 2 ]X 3 with XNO 3 , BF 4 . Single crystals of [Cu(memia)Cl 2 ] ( A ), [Cu(memia) 2 ]Cl 2 (H 2 O) 2 ( B ) and [Co(memia) 2 ](BF 4 ) 3 ( C ) were used in structure determinations. A crystallizes in the monoclinic space group P 2 1 / n ( Z =4) and B and C crystallize in the monoclinic space group P 2 1 / c ( Z =2 and 4, respectively). The cell dimensions for compound A are a =7.025(2), b =8.486(2), c =19.484(6) A, β=98.07(3)°, V =1150 A 3 , D x =1.76 g cm −3 . The cell dimensions for compound B are a =7.742(1), b =14.845(4), c =9.936(2) A, β=104.80(2)°, V =1104 A 3 , D x =1.53 g cm −3 . The cell dimensions for C are a =19.841(4), b =9.166(5), c =14.813(3) A, β=99.71(2)°, V =2656 A 3 , D x =1.65 g cm −3 . The structures were solved by heavy-atom techniques and refined by least-squares methods to residual R w values of 0.043 ( A ), 0.048 ( B )and 0.079 ( C ). The coordination geometry of the copper(II) ion in A is intermediate between square pyramidal and trigonal bipyramidal. The copper(II) ion is surrounded by an imidazole nitrogen (CuN=1.96 A), an amine nitrogen (CuN=1.99 A) and a thioether sulfur (CuS=2.43 A) from the ligand and by two chloride anions (CuCl(1)= 2.55, CuCl(2)=2.28 A). The coordination geometry of the metal ions in the bis(ligand) complexes B and C is distorted octahedral. The metal ions are coordinated by two imidazole nitrogens, two amine nitrogens and two thioether sulfurs. For compound B the imidazole nitrogens and the amine nitrogens are in the equatorial plane at 2.02 and 2.03 A, respectively, and the thioether sulfurs are at the axial positions at rather large distances, e.g. 2.77 A. For compound C the equatorial positions are also occupied by two imidazole nitrogens at 1.91 A and two amine nitrogens at 1.99 A. The thioether sulfur atoms are situated at the axial positions at 2.25 A.

Synthesis of titanium(IV) complexes containing 2,6-dimethylaniline substituted amino alcohols and their utilization in ethylene polymerizations

Abstract Two new Ti(IV) complexes of the type [(OCHRCH2N-2,6-Me2Ph)Ti(NMe2)2]2 (where R=H, or tbutyl) have been synthesized by protonolysis of Ti(NMe2)4 with the corresponding N-substituted amino alcohol ligand. The two complexes were studied as Ziegler–Natta type polymerization catalysts in the presence of an excess of methylaluminoxane (MAO). It was found that ethylene polymerization activity for both catalysts increased by increasing the polymerization temperature from 25 to 70°C. If the catalysts were pretreated with trimethylaluminum, the activities increased at 25°C, but slightly decreased at 70°C. Both complexes were found to be ineffective for the polymerization of propylene. An X-ray crystal structure of [(OCH2CH2N-2,6-Me2Ph)Ti(NMe2)2]2 shows the complex to be dimeric in the solid state, with bridging through the amino alcohol oxygen atoms. This complex crystallizes in the monoclinic system space group, P21/n with a=9.181(6), b=13.766(3), c=13.002(3), β=93.08(3) and Z=4.

THE CRYSTAL AND MOLECULAR STRUCTURE OF BENZYL (2-METHOXYPHENYL)-DIPHENYLPHOSPHONIUM BROMIDE

Abstract The crystal structure of benzyl(2-methoxyphenyl)diphenylphosphonium bromide has been determined from three dimensional X-ray data collected on a three circle diffractometer using MoKα radiation. The salt crystallized in the orthorhombic space group Pbca with cell constants α=15.528 (7), b=16.892 (7), and c=17.921 (8) A. The observed and calculated densities for 8 molecules per unit cell are 1.308 (5) and 1.309 g · cm−3 respectively. The structure was refined by full matrix least squares to final residuals of R=0.089 and R w0.120 for the 1757 independent reflections in the range 2° > 2θ> 42° whose intensities were above background. The cation has near tetrahedral geometry with an average P-C bond distance of 1.819 (14) A and the configuration of the ion is such that the oxygen atom of the methoxy group is trans to the alkyl carbon atom of the benzyl group. The phosphorus-oxygen distance of 2.878 (12) A suggests a weak bonding interaction and qualitative support for this view is obtained from energ...

An X-ray determination of the electron distribution in crystals of hexapyridine-N-oxide cobalt(II) perchlorate and the electronic structure of the Co2+ ion☆

Abstract The valence electron density distribution in hexapyridine-N-oxide cobalt(II) perchlorate, Co(C5H5NO)6(ClO4)2, has been investigated experimentally using high resolution single crystal X-ray diffraction data collected at 78(1) K with Mo Kα radiation, together with the results from the already reported neutron structure determination. The crystal data at 78 K are a = 12.317(1) and c = 18.826(1) A ; space group R 3 , Z = 3 . Deformation electronic density maps have been calculated from the X-ray data, using parameters from the refinement of the high data, sin θ/λ > 0.75 A −1 , the parameters obtained from the refinement of the neutron data and from structure factors obtained from a multipole deformation refinement. Conventional spherical atom refinement on 4030 reflections (Fo ⩾ 3σFo) gives R = 0.037 and Rw = 0.038, while the multipole refinement 3627 reflections gives R = 0.028 and Rw = 0.024. A pronounced aspherical electron distribution has been found for the cobalt atom in the deformation maps which is consistent with a significant trigonal distortion of the distribution expected for an octahedral ligand field, viz. t2g(5.0) and eg(2.0). The populations obtained from the multipole refinement confirm this and give apparent orbital occupancies of 3.7(1), 1.2(1) and 2.4(1) for the eg(t2g±), ag(t2g0) and eg′(eg) orbitals respectively, the charge on the cobalt ion being determined as +1.74(4). There is a large eg−e′g mixing coefficient which leads to the conclusion that there is a significant departure from the t2g octahedral character of the ground state orbitals. The results are consistent with a 4Ag ground state for the Co2+ ion, which is in accord with the various earlier magnetic, spectroscopic and heat capacity studies.

Unusual behaviour of the thioether function of the ligand 1,8-bis(3,5-dimethyl-1-pyrazolyl)-3,6-dithiaoctane (bddo) towards transition-metal salts. X-Ray structures of a green and a red modification of [Cu(bddo)Cl2]

Co-ordination compounds of the new ligand 1,8-bis(3,5-dimethyl-1 -pyrazolyl)-3,6-dithiaoctane (bddo) with MCl2(M = Fe, Mn, Ni, Co, Zn, Cu, or Cd), MBr2(M = Mn, Co, Ni, or Zn), Cu(BF4)2, and CuX (X = BF4, NCS, Cl, Br, or I) are described. The general formula for the divalent metal is [M(bddo)X2] and for copper(I), [Cu2(bddo)X2]. With CuCl2 two modifications were obtained. The green modification of [Cu(bddo)Cl2] crystallises in space group P21/n with a= 9.019(2), b= 28.671(5), c= 8.431(2)A, β= 113.65(2)°, R= 0.055, and R′= 0.066 for 1 578 unique reflections [I > 2σ(I)]. The compound consists of Cu(bddo)Cl2 units. The copper atom is co-ordinated by two pyrazole nitrogens and two chloride atoms, in trans positions, in a distorted square-planar geometry. The red modification of [Cu(bddo)Cl2] crystallises in space group Pbcn with a= 9.397(4), b= 15.093(4), c= 15.142(4)A, Z= 4, R= 0.069, and R′= 0.089 for 864 unique reflections [I > σ(I)]. This compound consists of CuCl2 units linked together by ligand molecules, thus forming chains with distinct C2 symmetry perpendicular to the chain axis. The copper atom is co-ordinated in a distorted-tetrahedral geometry by two pyrazole nitrogens and two chloride atoms in cis positions. The sulphur atoms do not participate in the co-ordination, although molecular-mechanics calculations show that the ligand bddo is not sterically hindered to form tetradentate mononuclear chelates, i.e. with a MN2S2 chromophore. The structures of the other divalent metal halides were established as being very similar to that of the red modification. For [Cu(bddo)(BF4)2] semi-co-ordination of one or both tetrafluoroborates is indicated by the i.r. spectrum. Solid-state 13C n.m.r. spectra of the copper(I) compounds indicate that the S atoms show significant shifts, suggesting co-ordination. In the thiocyanate and iodide compounds both thioether sulphurs co-ordinate in an identical manner, whereas in the chloride and bromide compounds they co-ordinate in a different manner.

Crystal and molecular structure of bistriphenyl(ethyl)phosphonium pentanitratocerium(III)

Crystals of the title compound are monoclinic of space group C2/c with a= 19·83(3), b= 11·05(2), c= 21·76(3)A, β= 108·17°, and Z= 4. The anion has crystallographic C2 symmetry and the cerium atom is ten-co-ordinate, being chelated symmetrically by the five bidentate nitrate ligands. The mean Ce–O distance is 2·57(2)A. The co-ordination geometry is not very readily described in terms of any idealised high co-ordination polyhedron, but if each nitrate ligand is considered, as occupying one co-ordination site, then the arrangement closely approximates to a trigonal bipyramid. The structure was solved from X-ray photographic data by Patterson and Fourier methods and refined by least-squares techniques to R 9·8% for 1516 observed reflections.